Dental compositions and methods of making same



3,328,246 DENTAL CQMPQiilTiUNS AND METHUDS OF MAKING SAME Siegfried Gottfried, llford, and Lily Baxendaie, London, England, assignors to Bicrex Laboratories Limited, London, England, a corporation of the United Kingdom No Ebrawing. Filed Sept. 18, 1963, Ser. No. 309,862 Claims priority, application Great Britain, Aug. 20, 1957, 26,332/57 5 Claims. (Cl. 167-60) This application is a continuation-in-part of application Ser. No. 753,609, filed Aug. 7, 1958, now abandoned. The invention is directed primarily to pharmaceutical compositions, particularly those which are useful in the treatment of ry socket, and to methods of making and using same. Of special import is a new vehicle used in the compositions.

Glycyrrhetinic acid and its active isomers; pharmaceutically acceptable salts thereof, such as the non-toxic alkali metal salts, e.g. the sodium salt of glycyrrhetinic acid; pharmaceutically acceptable esters thereof, e.g. glycyrrhetinic acid hydrogen succinate (see Patent 3,070,623) and glycyrrhetinic acid aminoethanol ester (see Patent 3,070,624); pharmaceutically acceptable glycyrrhetinic acid acryl derivatives e.g. acetyl glycyrrhetinate; xanthoglabrol (see Patent 3,066,072); pharmaceutically accept able salts of Xanthoglabrol with organic bases, e.g. the piperazine, protarnine, purine and N-methylglucamine salts; and pharmaceutically acceptable salts of xanthoglabrol with inorganic bases, such as alkali metal salts, e.g. xanthoglabrol sodium salt; have a marked effect in suppressing inflammation. They also potentiate other therapeutics so as to achieve a synergistic effect when employed admixed therewith in a single composition.

It is an object of the present invention to provide a composition containing an active ingredient, e.g. glycyrrhetinic acid, xanthoglabrol or one of their pharmaceutically acceptable derivatives, such as those suggested heretofore, which composition will permit the slow release over an extended period of time of the active ingredient. A further object is to provide an inert and insoluble carrier for the active ingredient. The prime object, however, is to formulate compositions for the treatment of dry socket. Still further objects will be apparent from the ensuing description.

one of the most distressing complications which may be encountered in dental extraction is dry socket which can cause excruciating pain. Although the aetiology of this condition is unknown, it would appear to be closely associated with the absence or loss of the blood clot, which in turn is linked with excessive vascular constriction probably caused by the large-scale use of drugs and possibly aggravated by sclerosis of the bone.

Many medicaments have been tried, the most popular to date being Zinc oxide and eugenol, or zinc oxide and Dentalone. Although these relieve pain, they have the disadvantage of leaving a large empty socket which requires repeated packing, and the cure is rather slow and not always effective. To avoid this there is provided according to the present invention, a composition in the form of a paste, which will not only relieve pain, but will encourage organisation of the socket and suppress inflammation, and which provides a vehicle which can be easily controlled and will slowly release the active therapeutic substances, while at the same time preventing infection in the surrounding area which is, of course, very prone to infection since it is surrounded by a large amount of bacterial flora.

The new composition, according to the present invention, comprises a pharmaceutical agent, preferably glyctes Patent 0 ice yrrhetinic acid and/or one of its active isomers and/or derivatives and/or xanthoglabrol and/or its derivatives together with a plastic material of the =polythene family with a suitable plasticizer, e.g. lithium hydroxy stearate, in a miscible type of oily or fatty material, e.g. liquid petrolatum. In the following discussion of this invention, each reference to glycyrrhetinic acid is understood to include additionally or in the alternative one of its active isomers and/or one or more of its pharmaceutically acceptable derivatives, such as a salt, ester or acyl derivative thereof. Each reference to xanthoglabrol likewise is understood to include additionally or in the alternative one or more of its pharmaceutically acceptable derivatives such as a salt thereof.

For the preparation of compositions according to the present invention, the oily or fatty material, such as liquid paraffin, e.g. liquid petrolatum, and polythene (polyethylene) are melted together at a temperature of from about 130 to 200 C., but below the decomposition or boiling point of either and preferably at about 180 C. with continuous stirring. The polythene may be added to the pre-heated oily or fatty material either portionwise or continuously or in one amount. The formed liquid admixture is permitted to cool naturally, i.e. in an ambient atmosphere of room temperature (20 to 30 C.) and atmospheric pressure, to about 65 C., at which temperature platicizer, e.g. lithium hydroxy stearate, [for the polythene is added gradually to said liquid admixture with constant stirring followed by the remaining ingredients, such as active ingredients, e.g. glycyrrhetinic acid or xanthoglabrol, while still stirring. It is critical that the plasticizer and the active ingredients be added at a temperature which is below their respective decomposition points. The plasticizer must be added at a temperature no higher than about 65 C. and the active ingredients must be added at a temperature no higher than about 65 C.

The polythene is that which is known as the branched chain (as opposed to linear) or the low-density type, e.g. Bakelite DYNH or Alkathene 20. Preferred polythene has a density from 0.910 to 0.925, but medium density, i.e. from 0.926 to 0.940, polythene can also be employed. Although a crystallinity from 4-5 to 55% is desirable, the crystallinity can vary considerably as long as the polythene is not completely amorphous. It is also preferred that the polythene have a melting point between and 120 and a molecular weight between 20,000 and 30,000. Alkathene 20 has a molecular weight of 24,000, a density of 0.92 gram/cubic centimeter, a refractive index of 1.52, a melting point between and C., and a decomposition temperature between 280 and 300 C.; it is soluble (at 60 to 75 C.) in many aromatic, aliphatic and halogenated hydrocarbons, but only slightly soluble in polar solvents. Bakelite DYNH has a molecular weight of about 21,000, a melting point of 110 C., a crystallinity of from 50 to 51 percent, a melt viscosity of 1,000,000 poises and a densiy of 0.92.

The polythene is preferably used in powdered or granular form but this is not essential and only serves to reduce the time necessary for dissolving the polythene in the oily or fatty material. It is to be understood that when the final viscosity of the vehicle is the greater, the greater is the molecular weight and/or crystallinity of the polythene used.

It is essential that the compositions be prepared with a plasticizer for the polythene. Any therapeutically acceptable inert (with respect to constituents) plasticizer for polythene may be employed.

A further essential ingredient for the preparation of the compositions of this invention is an oily or fatty material. Such materials as petroleum jelly, adeps lanae and lanolin can be employed, but it is preferred to use liquid petrolatum. This ingredient constitutes one of the main components of the vehicle in which the active ingredient(s) is (are) incorporated. It must also be pharmaceutically acceptable and chemically inert toward. the remaining ingredients.

The vehicle is prepared from the polythene, the plasticizer therefor and the oily or fatty material. The entire compositions are comprised of the vehicle and active ingredients. It is understood that inert materials can be added, but such addition is not an essential feature of the present invention. The make-up of the compositions with respect to essential constituents is indicated in the following table:

1 The parts by Weight are based upon 100 parts by weight of entire essential composition, i.e. vehicle plus active ingredieut(s).

2 Constituent of vehicle. The vehicle constitutes from 80 to 99 parts by weight, based upon 100 parts by weight of the cssential composition, or preferably from S to 90 parts by weight of the same basis.

By the use of compositions of the present invention wherein glycyrrhetinic acid and/or xanthoglabrol are comprised by the active ingredient, the healing organisation of the socket, the suppression of inflammation, and some degree of relief of pain, are achieved by the glycyrrhetinic acid, and/or the xanthoglabrol.

There may advantageously be provided in the compositions additional active ingredients, such as analgesics, e.g. cinchocaine, amethocaine hydrochloride, and aspirin, and/or anticausative agents, e.g. bactericides and antibiotics, such as ncomycin sulphate. The glycyrrhetinic compound and/ or the xanthoglabrol potentiates the action of these additional ingredients so that a synergistic effect is obtained. The potentiating action is quite independent of the presence of the polythene.

It is also advantageous when the compositions contain a preservative e.g. sodium benzoate or methyl-p-hydroxybenzoate.

The compositions of the present invention can be used in the treatment of infectious and infected gum conditions, periodontal diseases and inflammation and infection of the dental nerve canal. They are particularly valuable where they can be applied as a paste or by impregnating a gauze tissue with the composition and applying the impregnated tissue to the affected area. Compositions according to this invention are of especial interest in their utility as packing in the treatment or prevention of dry socket following the extraction of a tooth.

Xanthoglabrol and glycyrrhetinic acid have a powerful anti-phlogistic action, assist in tissue organisation, permit swift healing, and act synergistically with analgestics and antibiotics. By using the special vehicle of this invention, containing polythene with a plasticize-r, e.g. lithium hydroxy stearate, slow release and full coverage of the area can be achieved without having the active ingredients dissolved.

The following examples ar presented solely for the purpose of illustrating the invention. All parts are by weight and are based upon 100 parts by weight of essential ingredicnts; all temperatures are expressed in degrees centigrade. By essential ingredients are meant ingredients other than inert constituents.

EXAMPLE 1 Dental paste Twenty-two and two fifths (22.4) parts of liquid petrolatum are placed in a stainless steel Hobart mixer with a sun and planet movement and heated therein to 180 C. at atmospheric pressure, The agitator (paddle type) is made to rotate at about 89 revolutions per minute (rpm) and is maintained at this speed, except as otherwise stated, until the product is obtained.

Heating is stopped when the temperature of the liquid petrolatum reaches 180 C., and 34 parts of granulated polythene (Alkathene 20) are added to the hot liquid petroleum as it is allowed to cool naturally (in ambient surroundings). The polythene which is added slowly and continuously, dissolves in the liquid petrolatum, and the resulting solution is permitted to cool naturally, while continuing stirring, until its temperature reaches 65 C. At a temperature of 65 C. twenty-five parts of lithium hydroxy stearate are added to polythene/petrolatum solution. The resulting product is the vehicle, which is an essential part of the present invention.

The active ingredients are then incorporated into the vehicle.

Four parts of cinchocaine, 4 parts of amethocaine hydrochloride, 2 parts of glycyrrhetinic acid active isomers, 1 part of neomyc-in sulphate, 6.6 parts of aspirin and 1 part of methyl-p-l1ydroxybenzoate (preservative) are uniformly admixed and then added to the vehicle (at a temperature no higher than 65). The rate of stirring is increased first to rpm. and then to 300 rpm. to obtain thorough admixture. Natural cooling (to ambient temperature) is permitted to continue until the temperature of the admixture is essentially that of the surroundings (20 C.). The product obtained is a dental paste which is particularly useful in the treatment of dry socket.

The liquid petrolatum used for the preceding example is a colourless oily liquid, practically tasteless and odorless even when warmed. Its density is about 0.84. All of the solid ingredients are incorporated in the mix in as finely divided (powder for the active ingredients) form as practicable.

The temperature to which the liquid petrolatum is initially heated is not critical per se, but heating initially to a temperature of C. permits the discontinuance of the heating at that point and the carrying out of the entire preparation without any further heating.

The temperature of 65 at which the plasticizer is added is critical. Moreover the addition of the plasticizer at this temperature makes it necessary that the later-added active ingredients are added at a temperature which does not exceed 65 C. This is also critical.

The resulting paste is non-thixotropic and non-gelatinous.

In this example other low density polythenes can be used in place of Alkathene 20. When Bakelite DYNH is employed, the resulting product is essentially the same.

Instead of using a mixture of active ingredients, a single active ingredient can be employed. A composition prepared as above-described from 40 parts of Bakelite DYNH, .29 parts of liquid petrolatum, 30 parts of lithium hydroxy stearate and 1 part of glycyrrhetinic acid provides a dental paste having the anti-phlogistic properties of the glycyrrhetinic acid. The vehicle permits the slow release of the active ingredient.

Each of the compositions 2 to 37 is made according to the procedure of Example 1, but said procedure can be varied as indicated. In place of the Alkathene 20 other low or medium'density polythene having a molecular weight between 20,000 and 30,000 can be substituted with comparable results. The liquid petrolatum can be replaced in part or in whole by any other pharmaceutically acceptable inert oily or fatty material which is liquid at a temperature in excess of about 110 C.

PARTS BY WEIGHT OF INGREDIENTS Alkathene 2O 39 39 38 39 39 39 44 43 44 44 Liquid petrolatum 24 24 24 24 24 24 23 23 23 23 Adeps lanae 2 2 2 2 Lithium hydroxystezuute 28 28 28 28. 5 28 27 25 25 25 25 Glycyrrhetinic acid:

Active isomer 0.75 .5 2 1. 5

N-methylglucomine salt Piperazine salt Hcmisuccinote Disodium salt Xanthoglabrol Cinchocaine Amethocaine hydrochloride- Hydrocortisone N eomycin sulphate Aspirin Sodium bcnzoatc Methyl p-hydroxybenzoate..

Ingredient Alkathenc 20 35 36 38 38 Glycyn-hetinic acid: Active isomer... N-methylglucamine salt Piperazine salt Hcmisuccinate Sodium s'flt Acetyl.

Xanthoglabrol.

N -methy1glucamine salt. Sodium salt Cinchoeuine Amethocaine hydrochloride Neomycin sulphate Aspirin.

Sodium benzoate Methyl p-hydroxybenzoute Ingredient Alkathene 20 43 45 40 4O 41 43 34 32 35 Liquid petrolatum 30 20 22 24 17 25 23 25 22 Tmnnlin 6 Lithium hydroxystearate 20 26 32 30 30 26 26 27 25 Glycyrrhetinic acid:

Hemisuccinate Y 1 Di-sodium salt 2 Sodium salt 2 Acetyl. 2 XanthoglabroL. 2 2

Piperazine solr 2 Protamine wit 2 N-methyl-glucamine salt Sodium salt Cinchocaine Amethocaine hydrochloride... Neomycin sulphate Aspirin 3. 5 2 3 1 Sodium benzoate 1 Methyl p-hydrobenzoate 1 1 1 Ingredient Alkathene 20 38 38 40 35 40 44 43 Liquid petrolatum Lithium hydroxysteara 30 30 30 26 32 30 29 26 Glycyn'hctinic acid 2 2 Active isomer 2 1 N-methylglucamine salt.-. 2 Pipcrazine salt 4 Sodium salt 2 Xanthoglabml 2 2 Piper-azine s'ilt 1 N -methylglucamine salt. 1 Sodium salt 4 Cinchocaine 2 1 4 Neomycin sulphate 5 5 l 1 Aspirin 2 3. 5 Sodium benzoate. 1 Methyl p-hydroxybenzoate. 1 1

Although lithium hydroxystearate is exemplified as the polythene plasticizer, it can be replaced by a correspond ing amount of any pharmaceutically acceptable polythene plasticizer with comparable results. Plasticizer for the polythene, however, cannot be omitted.

In the preceding table the indicated parts by weight of derivatives of glycyrrhetinic acid and xanthoglabrol are those of the corresponding parent material so that a ready comparison can be effected.

Some of the compositions, e.g. those of Examples 8 to 12, are most useful as a gauze impregnant for packing a dry socket, whereas others, e.g. those of Examples 1 to 7, are readily used per se for this purpose.

EXAMPLE 38 Following the extraction of a tooth the resulting cavity in the jaw is syringed with a large quantity of liquid using a Higginsons syringe and then packed With the composition of Example 32.

In view of the nature of the vehicle, the composition remains in the cavity and permits the active ingredients to escape slowly and continuously to the surrounding area. The active isomers of glycyrrhetinic acid, which are powerful anti-inflammatory agents, not only depress inflammation but assist in the organisation of the socket, as well as promoting swift healing.

The new vehicle, i.e. the product formed from the polythene, plasticizer and fatty or oily material, has been found to produce good results in compositions containing glycyrrhetinic acid and/ or xanthoglabrol as the active ingredient or as one of the active ingredients. The use of the vehicle, however, is not limited to this purpose. As is apparent to the art-skilled, said vehicle can readily be employed with different active ingredients without the concurrent presence of either glycyrrhetinic acid or Xanthoglabrol.

In the preceding description reference is made to acyl derivatives and esters of active ingredients. The acyl derivatives of particular import are the glycyrrhetinic acid lower acyls. Among the esters of interest are the lower alkyl esters of glycyrrhetinic acid.

It is thought that the invention will be understood from the foregoing description. Various changes can be made in the process and in the products without departing from the spirit and the scope of the invention or sacrificing its material advantages, the process and products hereinbefore described being merely illustrative of the embodiments of the invention.

What is claimed is:

1. A non-thixotropic non-gelatinuous vehicle consisting essentially of (a) branched-chain polyethylene having a molecular weight between 20,000 and 30,000 (b) a member selected from the group consisting of petroleum jelly, lanolin and liquid petrolatum, and (c) lithium hydroxy stearate, the weight ratio of (a):(b):(c) being within the range of 30 to 45:20 to 30:20 to 35 based on from about 80 to 99 parts by weight of vehicle.

2. A non-thixotropic non-gelatinous vehicle consisting essentially of branched-chain low density polyethylene 8 having a molecular weight between 20,000 and 30,000, liquid petrolatum and lithium hydroxy stearate, the weight ratio of polyethylenezliquid petrolatumzlithium hydroxy stearate being within the range of 30 to 45:20 to 30:20 to 35, based on from 80 to 99 parts by weight of vehicle.

3. A process which consists essentially of dissolving low density polyethylene, having a molecular weight between 20,000 and 30,000 in liquid paraffin at a temperature in excess of C. and below the decomposition point of both the polyethylene and the parafiin, permitting the resulting solution to cool naturally at ambient temperature and atmospheric pressure to 65 C., admixing lithium hydroxy stearate as plasticizer for said polyethylene with said solution at a temperature of at most 65 C., and permitting the resulting product to cool to ambient temperature.

4. A process which consists essentially of dissolving low density polyethylene, having a molecular weight between 20,000 and 30,000, in liquid paraifin at a temperature in excess of 65 C. and below the decomposition point of both the polyethylene and the paraffin, permitting the resulting solution to cool naturally at ambient temperature and atmospheric pressure to 65 C., admixing lithium hydroxy stearate as plasticizer for said polyethylene with.

said solution at a temperature of at most 65 C., thereafter admixing topical dental therapeutically active ingredients with the resulting product and allowing same to cool naturally to ambient temperature.

5. A uniform pharmaceutically acceptable composition consisting essentially of vehicle and active ingredient; the vehicle being non-thixotropic and non-gelatinous and consisting essentially of (a) branched-chain polyethylene having a molecular weight between 20,000 and 30,000, (b) a member selected from the group consisting of petroleum jelly, lanolin and liquid petrolatum and (c) lithium hydroxy stearate, the weight ratio of (a) (b) :(c) being within the range of 30 to 45:20 to 30:20 to 35, and the active ingredient being a member selected from the group consisting of glycyrrhetinic acid, N-rnethylglucamine salt of glycyrrhetinic acid, piperazine salt of glycyrrhetinic acid, glycyrrhetinic acid hemisuccinate,

.-glycyrrhetinic acid hemisuccinate disodium salt, lower acyl glycyrrhetinic acid, xanthoglabrol, piperazine salt of xanthoglabrol, protamine salt of xanthoglabrol, and N- methyl-glucarnine salt of xanthoglabrol.

References Cited UNITED STATES PATENTS 2/1953 Frohmader et al. 16782 2/ 1953 Shoemaker 167--82 OTHER REFERENCES SAM ROSEN, Primary Examiner. 

1. A NON-THIXOTROPIC NON-GELATINUOUS VEHICLE CONSISTING ESSENTIALLY OF (A) BRANCHED-CHAIN POLYETHYLENE HAVING A MOLECULAR WEIGHT BETWEEN 20,000 AND 30,000 (B) A MEMBER SELECTED FROM THE GROUP CONSISTING OF PETROLEUM JELLY, LANOLIN AND LIQUID PETROLATUM, AND (C) LITHIUM HYDROXY STEARATE, THE WEIGHT RATIO OF (A):(B):(C) BEING WITHIN THE RANGE OF 30 TO 45:20 TO 30:20 TO 35 BASED ON FROM ABOUT 80 TO 99 PARTS BY WEIGHT OF VEHICLE. 